re-instate the documentation for 'Char', which got lost at some point

[ghc-prim.git] / GHC / Types.hs

diff --git a/GHC/Types.hs b/GHC/Types.hs
index 8040fec..b2d0291 100644 (file)
--- a/GHC/Types.hs
+++ b/GHC/Types.hs
@@ -1,3 +1,18 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  GHC.Types
+-- Copyright   :  (c) The University of Glasgow 2009
+-- License     :  see libraries/ghc-prim/LICENSE
+--
+-- Maintainer  :  cvs-ghc@haskell.org
+-- Stability   :  internal
+-- Portability :  non-portable (GHC Extensions)
+--
+-- GHC type definitions.
+-- Use GHC.Exts from the base package instead of importing this
+-- module directly.
+--
+-----------------------------------------------------------------------------
 
 {-# OPTIONS_GHC -XNoImplicitPrelude #-}
 
@@ -11,6 +26,18 @@ infixr 5 :
 
 data [] a = [] | a : [a]
 
+{-| The character type 'Char' is an enumeration whose values represent
+Unicode (or equivalently ISO\/IEC 10646) characters
+(see <http://www.unicode.org/> for details).
+This set extends the ISO 8859-1 (Latin-1) character set
+(the first 256 charachers), which is itself an extension of the ASCII
+character set (the first 128 characters).
+A character literal in Haskell has type 'Char'.
+
+To convert a 'Char' to or from the corresponding 'Int' value defined
+by Unicode, use 'Prelude.toEnum' and 'Prelude.fromEnum' from the
+'Prelude.Enum' class respectively (or equivalently 'ord' and 'chr').
+-}
 data Char = C# Char#
 
 data Int = I# Int#